A motor controller known in the art connected to a network may control driving of a motor based on a safety signal that is input through the network. A safety control system described in Patent Literature 1 performs processing associated with safety communication including transmission and reception through the network under cooperation between a controller for controlling a motor and a safety processing unit, and prevents delays in performing processing associated with safety.
To comply with the safety standards, a motor controller known in the art includes components that are associated with safety and components that are not associated with safety. A motor controller described in Patent Literature 2 includes a safety extension module, which monitors the driving status of a motor. The safety extension module is connected to a power supply for supplying power from the motor controller to the motor. The safety extension module receives a safety signal from, for example, a safety controller, and outputs a signal for cutting power supply from the motor controller to the motor to cut off the motor torque in a safe manner.